Pest Type: Flax Pest
Row: Coleoptera – Coleoptera
Family: leaf beetles – Chrysomelidae
It is found everywhere. Damages flax, less often beets.
Beetle 1.5-2 mm in size, black-green on top, less often blue or bronze; pronotum and elytra at small, barely noticeable points; legs are yellow, hips of hind legs are black. The egg is oval, 0.5-0.6 mm in size, bright yellow. Larva – 4-5 mm, thin, worm-like, milky white, head bright yellow; the abdominal segments are not clearly separated.
Adults hibernate under plant debris. Released in April. They feed on the plants themselves (cereals, cabbage, beets, etc.). With the advent of seedlings of flax is transferred to them. Active on warm sunny days. Mating and egg-laying take place shortly after flax populations.
The female places the eggs one at a time or in small groups (2-3 pcs.) In the surface soil layer on the main and lateral roots. Fertility – up to 300 eggs. After 11-25 days, larvae are born, within 26-29 days they feed on small roots of flax. Having completed development, the larvae pupate in the surface layer of the soil. After 17-20 days (end of June), adults emerge that feed until August, after which they leave fodder plants and migrate to wintering places. One generation per year is developing.
Adults and larvae do harm. In spring, imago gnaws holes on cotyledon leaves, eat around the edges of real leaves. Sometimes they damage the cotyledons and the growth point, causing the death of seedlings. The damage leads to a decrease in the length of the stem and a decrease in the number of bolls and seeds. Larvae damage the roots, which leads to stunted growth and plant diseases. A new-generation imago scrapes the skin and part of the stem parenchyma, which impairs the quality of the fiber.
Protective measures. Optimal early tight sowing dates. Weed control. During the period of mass migration of adults to the flax ladder, when the number exceeds 10 adults for 10 plants, the treatment of crops with insecticides.